DRV8825 Power Supply Problems

Hi everyone,

I’m working on a project in which I need to control at the same time three NEMA17 stepper motors. In order to do so, I am using three DVR8825 and a Arduino MEGA controlling all of them.

In order to simplify the electronics, I have designed a PCB as a MEGA shield. This is quite a simple PCB as it only contains three times the following minimal schematic included in the driver’s webpage:

Of course both Arduino and power supply are commonly grounded and the three drivers have the same VMOT and GND.

In order to reach the motor’s maximum force, I expect to supply the drivers at 40V, coming directly from a battery. Of course, for doing so I have included 100V and 100uF capacitors for each of the drivers in order to avoid that current peaks can damage the boards.

When I connect this to 12V, the whole system works perfectly and I can drive the motors with no problem. Although, when connecting to 40V, the system works for some time but, at one point, one of the drivers suddenly dies producing some kind of sparkling sound. The other two drivers still work but that one becomes completely useless after that. I must say that all the drivers get really hot at 40V even of having attached the heat sinks to all of them.

I would like to know if anyone has ever tried to connect the drivers to 40V and succeeded a making them move. Is overheating the reason for the drivers to suddenly stop working? Is it necessary some kind of active dissipation?

Thanks everyone.


40V is a fairly high voltage to be working in general and does not leave much margin with the DRV8825. Working with higher voltages makes it easier to inadvertently damage something, so make sure you are taking appropriate precautions.

Can you post some pictures of your drivers (including the damaged one) along with more information about your power supply and stepper motors? Could you try measuring your supply’s actual voltage or monitoring its output voltage with a scope while your system is running?

It is normal for stepper motor drivers to get hot during normal operation, even with heat sinks attached. Whether or not you need take additional steps to dissipate the heat depends on your operating conditions and how much performance you are looking for. What are you setting the current limit too (i.e. what is the voltage across VREF and GND)?

- Patrick

Hello Patrick.

During the last days I have been using the system at 24V and I had no problems at all. Motors move as expected and none of the drivers have stopped working in this time.

If the whole system works at both 12 and 24V, the problem is the fact of working at 40V. Theoretically I have taken into account all security aspects for this voltage since I have included 100uF capacitors for the power supply pins of each of the drivers.

I attach images from the driver that stopped working when my whole system stopped working. I see no differences between this one and the ones that are ok. Although, I’ve realized that if I measure its VREF, I obtain the same value as the voltage supply (24V). It is as if VREF had short-circuited to the input voltage.

In my system, drivers are inside a metallic box among other components. The inside of this box gets hot when running the system.

During these days I have also tested my drivers outside the box, and I have experienced no problems either. This is another fact that makes me think the problem is the temperature the drivers are achieving when working at 40V.

I have configured the drivers to VREF = 0.5 V in order to set the current limits to 1A per phase.

So, in few words, the system works at 12 and 24V but drivers stop working when supplying 40V. Also, the system hasn’t experienced any problems for now when being outside its metallic box.

Hope this can help trying figuring out the problem in the system. Thanks.

The driver you have is not manufactured by us. That makes it difficult to say for sure what might be causing the problem, and we cannot help you troubleshoot it since it is likely different than ours. However, VREF being equal to the supply voltage does make it appear fairly certain that driver is permanently damaged. It could be that the driver you have just does not work as reliably at 40V, but I would still encourage you to look at your setup with a scope so you can actually see what is going on rather than just speculating the supply is doing what you expect.

If you want to try a genuine Pololu DRV8825, then you can find them on our website, or you can get them from our authorized distributors. If the problems continue with one of our boards, I would be happy to help you continue troubleshooting.

- Patrick